Sky F1's Mark Hughes examines the different downforce levels run by Ferrari, Red Bull and Mercedes at Spa and what it means for Monza.

This could serve as a description of Sunday's Belgian Grand Prix but intriguingly it also exactly describes the season's previous low-downforce race, the Canadian Grand Prix.

While some extrapolated from Spa's form Red Bull having made development gains over the pack and Ferrari having leapfrogged past Mercedes as the second best car, it may not that be that at all. What we may have seen at Spa could have been just the standard form at a low-downforce track, a pattern that might be expected to continue into Monza, but which may not apply at any of the remaining seven races.

Montreal, Spa and Monza are the three outliers on the calendar in terms of the aerodynamic demands on the car. The trade off point between low drag and high downforce is biased towards the former at these three tracks. There is invariably variation in how well each design works at different parts of the aerodynamic map and with most tracks demanding high downforce, teams naturally concentrate on that aspect in conceiving and developing their cars.

Some cars naturally work better relative to the opposition in low downforce trim than they do in high, and this will only be evident at these three tracks. It can also be the case that some teams devote more of their resource to special low downforce packages for these tracks while others do a more cursory package, preferring to maximise resource - wind tunnel and simulation time - to the more commonplace higher downforce circuits.

"We are hoping the recent developments we have made will carry through to more conventional tracks," said Stefano Domenicali in Spa. But it would be no surprise if they didn't. Ferrari tends to devote more time to its low downforce package than most other teams, as a strong showing at Monza is deemed to be important.

But it may also be that there is something inherent in the design that is limiting it when in conventional form but which does not apply when running with skinnier wings. It can be that with a conventional set up, the airflow wake coming off the front wing may not be helpful in helping the rear of the car generate downforce.

But when that front wing is reduced in profile for the low downforce tracks, that problem is removed and the rear of the car receives good airflow to the downforce-producing devices (rear wing, rear brake ducts, diffuser).

In such an example, the car would suddenly be more competitive when the race is at a low downforce track, but the inherent problem would remain and become evident as soon as we returned to more conventional tracks.

Red Bull has historically struggled more at low downforce tracks than high but this year has dominated both Montreal and Spa. Its end of straight speeds at Spa were not the fastest but were much more competitive than last year. But it is not only the end-of-straight speeds that matter when discussing straightline performance.

What matters is how long it takes travel the straight. If you are entering that straight faster than anyone else and it is taking most of the straight before others are going as fast or faster, then you may still be getting down that straight in less time than anyone else even though by the end of it you are going slower than them.

At Spa the speed trap showed Red Bull was fastest onto the Kemmel straight and seventh fastest by the end of it. That combination may well have got the Red Bull down the straight in less time than any other car. Essentially, it was retaining more downforce - enabling it to be very quick through the twists of sector two - at not too costly a price in drag.

Mercedes did not find a good trade-off in downforce, balance and drag at Spa. Setting the car up with enough understeer to protect the rear tyres gave it a lot of tyre scrub through Eau Rouge, making it slow through there, up the hill and onto the long Kemmel straight that follows. It was making up more speed than most from the beginning of that straight to the end - suggesting low drag and/or good power - but not enough to overcome the lap time penalty caused by the lack of speed through Eau Rouge and the section immediately following.

So what does this suggest about Monza prospects? That the Ferrari and Red Bull should be quick and that Mercedes probably won't be so disadvantaged - because there is not the Monza equivalent of a speed-sapping, tyre scrubbing corner like Eau Rouge. Furthermore, the engine's good top end power will be seen to even better advantage.